- A genus of extinct marine reptiles, allied towards Mosasaurus. See Illust. in Appendix.
- an amazing genus of extinct reptiles, of the order Pythonomorpha, from the Cretaceous build up of the united states, having each ramus of lower jaw supplied with a peculiar articulation behind the midst of its length and between the splenial and angular bones, whence the name. About several species are explained, differing in length from 12 to 40 legs. Additionally Cleidastes.